Drug eruptions: 6 dangerous rashes

Treatment is supportive. Note that unlike those with SJS/TEN, patients with hypersensitivity syndrome may be treated with systemic corticosteroids.²⁷ As with TEN, patients should alert relatives to a possible increased risk of a severe reaction to the offending drug.²²

Vasculitis may present with palpable purpura, fever, and rash generally in dependent areas (Photo 3). Patients often develop morbilliform or urticarial eruptions, and the condition might affect internal organs. Differential diagnosis includes:

• Henoch-Schönlein (allergic) purpura
  
• Wegener’s granulomatosis
  
• infections
  
• collagen vascular diseases.²
  

© 2001-2008, DermAtlas
Vasculitis: Palpable purpura, fever, and rash generally in dependent areas.

Perform a complete history and physical in patients with suspected vasculitis. Because vasculitis can affect the blood vessels of any organ,²⁰ laboratory tests such as CBC, UA, and fecal occult blood test to assess organ involvement are indicated.²
Pharmacotherapy depends on the severity of presentation and ranges from topical agents to immunosuppressants.² Other treatments are rest, elevation, support stockings, and antihistamines.²⁸

Erythroderma, also known as exfoliative dermatitis, can present as sudden, pruritic erythema that can generalize (Photo 4). Scaling will appear, followed by desquamation. Patients typically complain of irritation, feeling cold, and a sensation of tightness. Dilated dermal vessels can result in high-output cardiac failure. This potentially life-threatening condition can develop within 1 week of starting a drug.^2,29

© 2001-2008, DermAtlas
Erythroderma: Sudden, pruritic erythema that can generalize. Scaling precedes desquamation.

Pharmacotherapy includes emollients, antihistamines, and corticosteroids.² Erythroderma is best treated in a hospital, where patients typically receive supportive care, with special attention to nutritional and hydration status.²⁹

Erythema nodosum may present as painful erythematous nodules—usually in the lower extremities (Photo 5)—that are the result of fat necrosis.^13,30 Treatment typically involves best rest, nonsteroidal anti-inflammatory drugs, and potassium iodide.³⁰ Systemic corticosteroids also may be used.³¹

© 2001-2008, DermAtlas
Erythema nodosum: Painful erythematous nodules, usually in the lower extremities.

Resuming psychiatric treatment

Although medically necessary for patients with a serious rash, abruptly discontinuing a psychotropic might place them at risk for rapid psychiatric decompensation. Whenever possible, wait 2 weeks before restarting psychopharmacotherapy in a patient who has been treated for an ACDR. If that is not feasible because (for example) the patient is psychotic and agitated, you can cross-taper with a different medication from another class.

If your patient has experienced a serious ACDR, follow the 3 “A’s” to protect against recurrence (Table 4).

Box

Table 4

3 ‘As’ to protect patients after a life-threatening ACDR

Allergy. Add the offending drug to the patient’s allergy list to ensure it is not given again
Alert. Tell the patient he or she should wear a medical alert bracelet to prevent being given the drug
Advise. Inform the patients’ close relatives that they may be at risk for a similar reaction to the same drug or drugs from the same class
ACDR: adverse cutaneous drug reactions

Related resources

• Knowles SR, Shear NH. Recognition and management of severe cutaneous drug reactions. Dermatol Clin 2007;25(2):245-53.
  
• Dermatology Image Atlas. www.dermatlas.org.
  
• American Academy of Dermatology. www.aad.org.
  

Drug brand names

• Alprazolam • Xanax
  
• Amitriptyline • Elavil
  
• Aripiprazole • Abilify
  
• Bupropion • Wellbutrin
  
• Carbamazepine • Tegretol
  
• Chlorpromazine • Thorazine
  
• Clomipramine • Anafranil
  
• Clozapine • Clozaril
  
• Cyclosporine • Neoral, Sandimmune
  
• Desipramine • Norpramin
  
• Diazepam • Valium
  
• Duloxetine • Cymbalta
  
• Eszopiclone • Lunesta
  
• Fluoxetine • Prozac
  
• Fluvoxamine • Luvox
  
• Haloperidol • Haldol
  
• Lamotrigine • Lamictal
  
• Methylphenidate • Ritalin
  
• Mirtazapine • Remeron
  
• Maprotiline • Ludiomil
  
• Olanzapine • Zyprexa
  
• Oxcarbazepine • Trileptal
  
• Paroxetine • Paxil
  
• Phenytoin • Dilantin
  
• Phenobarbital • Luminal
  
• Quetiapine • Seroquel
  
• Risperidone • Risperdal
  
• Sertraline • Zoloft
  
• Thioridazine • Mellaril
  
• Topiramate • Topamax
  
• Lithium • Lithobid, Eskalith
  
• Trazodone • Desyrel
  
• Valproic acid • Depakote
  
• Venlafaxine • Effexor
  
• Ziprasidone • Geodon
  

Disclosure

Dr. Skonicki reports no financial relationship with any company whose products are mentioned in this article or with manufacturers of competing products.

Dr. Warnock receives research/grant support from Boehringer Ingelheim, Forest Pharmaceuticals, and Wyeth Pharmaceuticals.